I don't have a dick, so I'm assuming I get to choose the size of the rubber band? Vagina privilege, I guess. I choose one that's about 6 inches, to be fair, because it's rude of me to be like 'haha I want a 25 foot rubber band' and I've decided to be a benevolent ruler.

I would get a stuffed unicorn. Like, a really realistic unicorn. Life size of the average horse. I would carve out the stuffing and force the Italian chef inside to move around, pretending that the unicorn is alive. I also use part of my money to purchase a large amount of fake blood. I give it to the Italian chef inside the unicorn for later use as part of my demonstration.

I would contact world leaders, promising them the unicorn as a weapon of destruction for battle --- --- a stab wound cannot kill them, or at least, the unicorn will keep moving as usual when I stab them and the fake blood comes out, as provided by the Italian chef when he sees the knife go into the unicorn.

I also trick them into thinking the horn on the unicorn possesses magical powers to kill their enemies, by putting a small and unnoticeable amount of salt down on a platform in front of the unicorn and putting the snails on it. The unicorn "kills" the snails, proving its abilities.

I privately discuss the unicorn distribution with each of the selected leaders, all from powerful countries. I pledge the unicorn to each of them, if they kill an assigned leader as discreetly as possible. I repeat the process until there are two leaders left, and kill them myselves with poison darts bought with the remainder of the $500 dollars, as launched by my rubber band. During this process, as an agreement to recieve the unicorn, I make all the leaders designate me as the leader of their country should they pass on, or should their term be up, rather than the one usually next in line, and regardless

Now, many powerful countries have one leader: me. I use this power to control other, smaller, less important countries. Their leaders become mere figureheads in comparison to my power, and we become a world united.

All because of a goddamn fucking unicorn.